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This study focuses on presenting how nuclear power has been reintroduced in the energy debate during the last few years, as it is being discussed how this low-carbon energy generating technology can help mitigate the effects of climate change. Furthermore, it analyses the advantages of nuclear power, but especially the disadvantages that nuclear technologies need to overcome to rise to the challenge of climate change. In particular, the disposal of radioactive waste. The concept of radioactive waste and the current methods for its disposal are explained before studying what international legal instruments regulate about the issue. Following this, especial reference is made upon the specific legal frameworks affecting the disposal of radioactive waste in France and Spain and the current solutions they offer for a waste that is mainly generated by their nuclear power plants.

Can Pakistan’s environmental-related technologies (ERT) and nuclear and renewable energy mitigate environmental pollution? As global warming and climate change rise dramatically, economies shift to friendly energy substitutions and eco-friendly technologies, contributing to the mitigation of environmental contamination. In this scenario, policy and academic analysts have paid more concentration to renewable and nuclear energy deployment with ERT installation. To achieve this goal, the present study scrutinizes the asymmetric effects of nuclear energy, renewable energy, and ERT on the ecological footprint of Pakistan. The current research applies a novel non-linear autoregressive distributive lag method from 1991 to 2020. The results of the current analysis show that negative changes in nuclear energy increase emissions levels in the long run, while positive and negative changes in renewable energy deployment significantly overcome the burden on the environment. Similarly, positive and negative changes in ERT reduce pollution levels in the long run. Moreover, these long-run outcomes are analogous to short-run findings for Pakistan. Therefore, there is a dire requirement to increase the consumption of renewable and nuclear energy sources and take advantage of the noteworthy impact of an uncontaminated atmosphere through clean ERT potentials.

For the purpose of finding benchmark quality solutions to time dependent Sn transport problems, we develop a numerical method in a Discontinuous Galerkin (DG) framework that utilizes time dependent cell edges, which we call a moving mesh, and an uncollided source treatment. The DG method for discretizing space is a powerful solution technique on smooth problems and is robust on non-smooth problems. In order to realize the potential of the DG method to spectrally resolve smooth problems, our moving mesh and uncollided source treatment is devised to circumvent discontinuities in the solution or the first derivative of the solutions that are admitted in transport calculations. The resulting method achieves spectral convergence on smooth problems, like a standard DG implementation. When applied to problems with nonsmooth sources that induce discontinuities, our moving mesh, uncollided source method returns a significantly more accurate solution than the standard DG method. On problems with smooth sources, we observe spectral convergence even in problems with wave fronts. In problems where the angular flux is inherently non-smooth, as in Ganapol's (2001) well known plane pulse benchmark, we do not observe an elevated order of accuracy when compared with static meshes, but there is a reduction in error that is nearly three orders of magnitude.

Abstract Sodium-cooled Fast Reactors and Lead-cooled Fast Reactors have been selected by the Sustainable Nuclear Energy Technology Platform as technologies that can meet future European energy needs. To achieve the requested level of safety for these reactor technologies and to minimize the increase in the costs due to additional safety measures, accurate and reliable nuclear data are necessary. The objective of this work has been to analyse and improve the nuclear data required for the development, safety assessment and licensing of SFRs and LFRs, reducing the uncertainties in the reactor integral responses due to the uncertainties in nuclear data, in order to reach the target accuracies defined by researchers, industry and regulators. To that end, target accuracy and data assimilation analyses have been performed to identify nuclear data weaknesses and to reduce the uncertainties of integral safety-related parameters due to neutron induced nuclear data. As a result of this work, nuclear data needs for advanced SFRs and LFRs have been identified, improvements of existing nuclear data libraries have been suggested, nuclear data have been adjusted and uncertainties in reactor integral parameters have been reduced, meeting target accuracies after adjustment.

New measurements of very exotic nuclei in the neutron-rich region beyond N=126 have been performed at the GSI facility with the fragment separator (FRS). The aim of the experiment is to determine half-lives and beta-delayed neutron emission branching ratios of isotopes of Hg, Tl and Pb in this region. This contribution summarizes final counting statistics for identification and for implantation, as well as the present status of the data analysis of the half-lives. In summary, isotopes of Pt, Au, Hg, Ti, Pb, Bi, Po, At, Rn and Fr were clearly identified and several of them (Hg208-211, Tl211-215, Pb214-218) were implanted with enough statistics to determine their half-lives. About half of them are expected to be neutron emitters, in such cases it will become possible to obtain the neutron emission probabilities, P-n.

Neutron-induced fission cross sections for natPb and 209Bi were measured with a white-spectrum neutron source at theCERNNeutron Time-of-Flight (n TOF) facility. The experiment, using neutrons from threshold up to 1 GeV, provides the first results for these nuclei above 200 MeV. The cross sections weremeasured relative to 235U and 238U in a dedicated fission chamber with parallel plate avalanche counter detectors. Results are compared with previous experimental data. Upgraded parametrizations of the cross sections are presented, from threshold energy up to 1 GeV. The proposed new sets of fitting parameters improve former results along the whole energy range.

Les alliages de zirconium sont utilisés comme matériaux de gainage des combustibles nucléaires dans les réacteurs à eau pressurisée. Ces gaines sont utilisées dans un milieu extrêmement radiatif et corrosif, elles peuvent dans certains cas être le siège de fortes variations de température et doivent répondre à des sollicitations mécaniques importantes, que ce soit en conditions de service ou accidentelles. Dans un tel contexte, il est intéressant de pouvoir prédire les transformations de phases ayant lieu au sein de la gaine en fonction des variations de température et de composition chimique, la précipitation de phases fragiles induites par la présence des éléments d’alliages, mais aussi de tester de nouvelles compositions d’alliages afin de l’optimiser.La méthode la plus adaptée pour la modélisation thermodynamique de systèmes multiconstitués est la méthode Calphad (CALculation of PHAse Diagrams). Il s’agit d’une méthode semi-empirique, consistant à modéliser les enthalpies libres des différentes phases constitutives d’un système par ajustement de certains paramètres, dans le but de reproduire les données expérimentales.Ce mémoire détaille la construction d’une base de données thermodynamiques du système quinaire Cr-Fe-Nb-Sn-Zr selon la méthode Calphad. L’originalité de notre démarche est liée à l’utilisation des calculs DFT de manière systématique et massive. Il s’agit en particulier de calculer par DFT les enthalpies de formation de tous les end-members des phases intermétalliques constitutives du système quinaire. De plus, des calculs sur des mailles « quasi aléatoires » (SQS) sont également effectués de manière systématique afin de déterminer les enthalpies de mélange des solutions solides binaires en structure fcc, bcc et hcp. En outre, une étape importante de ce travail consiste à compléter les données expérimentales de la littérature par de nouvelles mesures sur des systèmes choisis. En particulier, nous nous sommes employés à décrire quelques équilibres de phases des systèmes ternaires Cr-Nb-Sn, Cr-Fe-Sn, Cr-Sn-Zr et Fe-Nb-Sn qui n’avaient jamais été déterminés expérimentalement. Nous avons ensuite utilisé ces calculs et ces nouvelles données expérimentales en complément de données de la littérature comme données d’entrée pour la modélisation thermodynamique des vingt sous-systèmes binaires et ternaires du système quinaire considéré. Enfin, le pouvoir prédictif de notre base de données a pu être vérifié en confrontant ces prédictions à des données expérimentales relatives à des alliages quinaires industriels ou à de nouveaux concepts de gaines Currently, zirconium alloys are used as fuel cladding materials in PWR (Pressurized Water Reactors). The claddings stand in a very corrosive and radiative environnement, and can be submitted to temperature variations. In addition, the claddings will be subjected to mechanical stresses in reactor or accidental conditions. Thus, it appears useful to have a better understanding of phase transformations occurring in these alloys, as a function of temperature and chemical composition variations, but also to forecast the precipitation of fragile phases induced by the addition of alloying elements. At last, the ability to test new alloy compositions may allow to optimize it.The most suitable method for the thermodynamic modeling of multicomponent systems is the Calphad method (CALculation of PHAse Diagrams). The Calphad method is a widely used technique of semi-empirical modelling of phase diagrams. It consists in the description of the Gibbs energies of the different phases by fitting parameters allowing to describe the experimental data.This report details the design of a thermodynamic database considering the five following elements Zr, Cr, Fe, Nb, and Sn. The originality of this database lies in a systematic use of DFT calculations. Indeed, DFT calculations are performed to predict the formation enthalpy of the intermetallic phases appearing in these systems. Moreover, the SQS method (Special Quasirandom Structure) is used to predict the mixing enthalpy of the fcc, bcc and hcp binary solid solutions. Besides, experimental investigations are an important step of this thesis. Since no experimental data were available for the Cr-Fe-Sn, Cr-Nb-Sn, Cr-Sn-Zr and Fe-Nb-Sn ternary systems, new experimental data are provided, within this study, on the isothermal sections of these systems at different temperatures. All these calculated data in addition to the experimental data and the data from literature are used as input data for the Calphad modelling of the twenty binary and ternary systems which are then combined in the new database. A last part is dedicated to comparisons between predictions obtained with our new database and experimental results on industrial quinary alloys and a new concept of claddings

The Am241(n,¿) cross section has been measured at the n-TOF facility at CERN using deuterated benzene liquid scintillators, commonly known as C6D6 detectors, and time-of-flight spectrometry. The results in the resolved resonance range bring new constraints to evaluations below 150 eV, and the energy upper limit was extended from 150 to 320 eV with a total of 172 new resonances not present in current evaluations. The thermal capture cross section was found to be sth=678±68 b, which is in good agreement with evaluations and most previous measurements. The capture cross section in the unresolved resonance region was extracted in the remaining energy range up to 150 keV, and found to be larger than current evaluations and previous measurements. © 2014 American Physical Society.